> Every excretion flushed in the city of Chicago ends up as fertilizer on midwest farms. Mostly soybeans, IIRC.

Is this meaningfully true? My understanding is that the wastewater is treated and emptied into the Chicago river where it flows toward Missouri. Insofar as that water is rich in organic compounds, it "fertilizes" the fields that draw from that river and its distributaries; however, this model is different than the picture you paint, which sounds more like dumping more-or-less raw sewage directly on fields. If the latter is indeed the case, it's news to me, especially since I understand human sewage fertilizer to be prohibited as a health risk.